1. Field of the Invention
The present invention relates to a biaxial type hinge apparatus and a foldable electronic device having that hinge apparatus.
2. Description of the Related Art
There are known foldable cellular phone devices which can fold a display unit and a main body with respect to each other, and can rotate the display unit. In regard to such foldable cellular phone devices, Unexamined Japanese Patent Application KOKAI Publication No. 2005-188641, and Unexamined Japanese Patent Application KOKAI Publication No. 2007-177829 disclose the following technologies: a technology which allows the display unit to rotate with a restriction unit being released when a folded state is released and the display unit is at a predetermined angle relative to the main body; and a technology which restricts any folding of the display unit when the display unit is in a rotatable state.
The foregoing publications disclose a foldable cellular phone device having a biaxial hinge, and a rotation motion and a folding motion are restricted. The biaxial hinge means a hinge which allows rotation motions in two directions. An example of the biaxial hinge is one which allows a first casing and a second casing to open or rotate relative to each other in a vertical direction and a horizontal direction from the state where the first and second casings are folded down. According to such a cellular phone device, however, in order to restrict motions in the two directions in accordance with respective states, individual mechanisms for each of the motion directions are required. Therefore, the hinge mechanism becomes complex and becomes larger and larger.